Low threshold acquisition controller for Skipper charge-coupled devices

Abstract

The development of the Skipper-charge-coupled devices (Skipper-CCDs) has been a major technological breakthrough for sensing very weak ionizing particles. The sensor allows to reach the ultimate sensitivity of silicon material as a charge signal sensor by unambiguous determination of the charge signal collected by each cell or pixel, even for single electron-hole pair ionization. Extensive use of the technology was limited by the lack of specific equipment to operate the sensor at the ultimate performance. A simple, single-board Skipper-CCD controller designed by the authors is presented and aimed for the operation of the detector in high sensitivity scientific applications. Our article describes the main components and functionality of the so-called low threshold acquisition controller together with experimental results when connected to a Skipper-CCD sensor. Measurements show unprecedented deep subelectron noise of 0.039 e − rms ∕pix by nondestructively measuring the charge 5000 times in each pixel.

Search for coherent elastic neutrino-nucleus scattering at a nuclear reactor with CONNIE 2019 data

“…This decreases the noise down to sub-electron levels and makes them capable of counting the number of electrons in each pixel. The CONNIE detector was updated with two skipper-CCD sensors and their dedicated readout electronics [32] in mid 2021 and is currently commissioning the new setup, performing background measurements and detector characterisation since July 2021. This is the first step in the direction of a future skipper-CCD experiment of larger mass that will be able to achieve the increased sensitivity necessary to detect the coherent scattering of reactor antineutrinos.…”

Multiplexed Readout for an Experiment with a Large Number of Channels Using Single-Electron Sensitivity Skipper-CCDs

“…There are also other types of non-destructive imaging sensors [6,7]. A specific readout electronics system, the low-threshold acquisition controller (LTA), was designed to control and process [8,9] the Skipper-CCD signals [10]. This system has achieved the best performance with the sensor, but due to its fully digital, high-speed video signal sampling and processing, its architecture could not be easily extended for experiments that feature kilograms of Skipper-CCDs with thousands of video channels as sensitive mass.…”

“…Popular scientific CCD controllers such as Leach [18] and Monsoom [19] use the mixed analog/digital DSI method to calculate the pixel value. The LTA [10] uses a high-speed ADC (15MSps) and computes the pixel value with a microprocessor. All these three systems transfer the digital pixel value as soon as they compute it.…”

“…The circuit also reduces the data throughput by measuring the skipper samples using a charge pile-up technique, which allows only the final pixel value with reduced noise to be sent to the analog-to-digital conversion (ADC) stage. The reduction in data rate, along with the multiplexer, allows the reading of up to 6400 video channels with the same single ADC that was previously used to read a single fully digital video channel [10].…”

Smart Readout of Nondestructive Image Sensors with Single Photon-Electron Sensitivity

“…Inside a dewar, the skipper-CCD is operated at high vacuum (approximately 10 −4 mbar) and at a temperature of 140 K. The sensor is a fully depleted CCD developed by Lawrence Berkeley National Laboratory, LBNL [6]. The low threshold acquisition controller (LTA) [25] is used for readout and control.…”